Systems and methods for luminal access

ABSTRACT

A luminal access system comprises an evertable, lubricious sleeve, a pusher tube, and optionally a lumen tube. The evertable, lubricious sleeve is attached to a non-evertable sheath which is coaxially received over the pusher tube. A distal portion of the evertable sleeve folds or everts into an axial passage of the pusher tube where it is connected to a lumen tube. A distal portion of the pusher tube may be bendable, typically comprising a relatively soft polymer which is circumferentially reinforced to enhance hoop strength.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical apparatus and methodsfor using such apparatus. In particular, the present invention relatesto systems and methods for accessing target locations in or throughnatural and created body lumens.

A wide variety of catheters and probes are used in an almost unlimitednumber of medical procedures and protocols. Of particular interestherein, tubular catheters are often used to provide access through bodylumens, for example, through a patient's urethral canal to permitdraining the bladder. Such catheters are typically referred to asurinary catheters and are inserted into the bladder via the urethra.Ureteral catheters can be inserted into the ureter via the bladder toreach the kidneys. The catheters can have a variety of purposes,including access to/capture of and/or destruction of urinary calculi.The introduction of such urinary and uretal catheters is often the causeof urinary infections. For example, the introduction of urinarycatheters into the urethra can carry bacteria or other infectionsmaterials from the patient's skin or the lower urinary tract into thebladder or from the bladder into the upper urinary tract. The leadingtip of such conventional catheters can act as a pusher or transferdevice that can unintentionally spread infection.

Even if proper precautions are taken to reduce or eliminate infection,the advancement of conventional catheters through the urethra, ureter,or other small body lumens can irritate the luminal wall and causediscomfort or, in the worst cases, injury to the walls. Even if noserious damage is caused, the resulting scarring can lead to strictureformation and discomfort can be substantial.

To overcome both of these problems, RTC, Inc. of St. Paul, Minn., hasdeveloped the Memcath™ Intermittent Urology Catheter which uses a PTFEsheath which everts from the interior of the catheter over the exterioras the catheter is introduced. As illustrated in FIG. 1, the Memcath™catheter 10 has a tubular PTFE membrane 12 which is initially stowedwithin the lumen 14 of the catheter. The membrane extends out a distalend of the catheter 10 and has an everting section 18 which attaches toa ring 20 which can slide over the exterior surface of the catheter. Inthis way, as the catheter 10 is advanced into a body lumen, such as theurethra, the tubular membrane 10 will be pulled around the distal end 16of the catheter to cover the exterior of the catheter as it advances.Since the ring 20 is held stationary relative to the body lumen, themembrane, once it is deployed, will also remain stationary, reducing therisk of trauma to the luminal wall and preventing the propagation ofbacteria and other pathogens upward into the body lumen.

While this design is fundamentally sound, it does suffer from certainshortcomings. The ring 20 is intended to be held manually over theaccess orifice of the body lumen. Thus, the Memcath™ catheter issuitable for introduction through the urethra, but would be difficult todeploy in the ureter or other internal body lumen, particularly using anendoscope or other minimally invasive approach. The distal end of thecatheter 10 is relatively stiff, so introduction of the catheter througha relatively tortuous path and/or past obstructing material, such asurinary calculi, can be difficult. Additionally, if the membrane 12 isnot fully deployed, a trailing end can remain within the lumen 14 of thecatheter, making access through the lumen difficult.

For these reasons, it would be desirable to provide improved designs andmethods of use for luminal access catheters of the type which include aprotective, deployable outer membrane. In particular, it would bedesirable to provide such catheters which are suitable for endoscopicand other minimally invasive deployments. It would further be desirableto provide such catheters having relatively flexible or deflectabledistal ends to permit introduction into relatively tortuous lumensand/or introduction past obstructing materials within such lumens. Itwould further be desirable if the catheters were suitable forintroduction over guidewires in at least some circumstances.Additionally, it would be desirable to provide such catheters whichmaintain an open lumen, even if the protective sheath is not fullydeployed while the catheter is introduced. It would be further desirableif the membrane position could be reset after use to allow multipleadvancements with the same catheter in a single patient. At least someof these objectives will be met by the inventions described below.

2. Description of the Background Art

The use of an everting sleeve composed of thin, tensilizedpolytetrafluoroethylene for introducing catheters to body lumens isdescribed in U.S. Pat. Nos. 5,531,717; 5,676,688; 5,711,841; 5,897,535;6,007,488; 6,240,968; and EP605427B1. Other catheters employing evertingsleeves for a variety of purposes are described in commonly assigned,copending application nos. 10/794,337 (Attorney Docket No.021807-000300US), filed on Mar. 5, 2004, 10/794,317 (Attorney Docket No.021807-000400US), filed on Mar. 5, 2004, and 10/886,886 (Attorney DocketNo. 021807-000800US), filed on Jul. 7, 2004, the full disclosures ofwhich are incorporated herein by reference.

BRIEF SUMMARY OF THE INVENTION

The present invention provides systems and methods for accessing targetlocations within a patient's body. The target locations will often beinside of a body cavity, organ, or body lumen, but can also be withinsolid tissue. Typical target locations include those intended fortherapy, such as drainage, drug delivery, ablation, excision, thermaltreatment, photodynamic therapy, and the like. Exemplary therapeutictreatments include drainage of the bladder through the urethra andtreatment of the kidneys through the ureter. The present invention isparticularly suitable for endoscopic deployment of a drainage catheterinto the kidneys through the ureter. Alternatively, the target locationsaccessed using the present invention may be intended for diagnosis,including biopsy, aspiration, imaging, chemical analysis, and the like.

In either case, the target location will usually be reached at leastpartly through a natural body lumen, such as a urethra, a ureter, ablood vessel, a hepatic duct, a cystic duct, a cervical canal, afallopian tube, or the like. The access system can be advanced ordeployed to a site adjacent to the natural body lumen in a minimallyinvasive manner, typically using an endoscope, a cystoscope, athoracoscope, or other percutaneous device. Less commonly, the presentinvention could be used to provide access through solid tissue,particularly non-fibrous tissue such as brain tissue, or betweenadjacent tissue planes or layers. For access through solid tissue, itwill usually be necessary to form a tissue tract either before or at thesame time as introducing the access system of the present invention.

An exemplary technique employing the access system of the presentinvention will be described in connection with transuretal access to thekidneys where the system is first introduced to the bladder using anendoscope. It will be appreciated, however, that the principles of theembodiments of the present invention may be applied to a much widervariety of target locations and access routes.

In a first aspect, the present invention provides a luminal accesssystem comprising an evertable, lubricious sleeve and a pusher tube. Thepusher tube has a distal end, a proximal end, and an axial passagebetween the distal and proximal ends. The sleeve is stowed within theaxial passage of the pusher tube and is able to evert over the distalend of the tube. It can thereby extend over the exterior of the tube toprovide a protective interface as the tube is advanced through a bodylumen. In some embodiments, the distal end of the pusher tube may besteerable, e.g., being flexibly curved or shaped or having pull wire(s)or other mechanisms for selectively deforming the distal end to permitsteering of the access system through a branching luminal network suchas the vasculature. The evertable, lubricious sleeve and the pusher tubeare common system components to several different embodiments of thepresent invention, each of which will be described in more detail below.

In a first embodiment of the luminal access system, the pusher tube ischaracterized by a distal portion which is circumferentially reinforced,for example to enhance hoop strength, while at the same time beingrelatively more bendable than a proximal portion of the pusher tube. Therelatively bendable distal portion of the pusher tube has a number ofadvantages. First, it allows the pusher tube to be advanced through bodylumens which are more tortuous than would be accessible with theMemcath™ catheter or many other luminal access catheters of the priorart. Second, the bendability and enhanced flexibility of the distalportion will allow the pusher tube to be advanced past potential luminalobstructions in the body lumen being accessed with less risk of lumenpenetration. For example, when advancing the pusher tube through aureter, the pusher tube will be able to more easily pass by urinarycalculi which might block the lumen. Third, the bendable distal end willallow the device to track over a guidewire through tortuous lumensshould this be desired. Fourth, the bendable section can be combinedwith a pull wire to permit selective deflection and steering of the tubein the body lumen.

Typically, the pusher tube will comprise a polymeric tube, at least overits distal portions. The polymer may be selected from a variety ofsuitable polymers, including polyethylenes, polyurethane(s),polyolefins, EVA, Pebax, and the like. In the exemplary embodiment, thedistal portion of the pusher tube will typically comprise a composite oftwo or more of these polymers while the proximal portion of the pushertube will comprise a high density polyethylene or polyimide. The distalportion of the pusher tube will usually be circumferentially reinforced,typically by a coil structure, more typically a ribbon wire coil, wherethe pitch varies to control stiffness and bendability along the distallength. An exemplary reinforcement ribbon will be composed of stainlesssteel, nickel-titanium alloy, or other suitable metal, and will have awidth in range from 0.1 mm to 1 mm, a thickness in the range from 0.003mm to 0.4 mm, and a spacing between adjacent turns that varies in therange from 0.2 mm to 2 mm. It will be appreciated, however, that othercircumferential reinforcement structures could be utilized, includingaxially spaced apart hoops, braids, disks, or the like. Whateverreinforced structure is chosen, however, it is desirable that thebendability of the distal portion not be compromised to limit theability of the pusher tube to traverse tortuous body lumens, be advancedpast luminal obstructions, and the like.

The evertable, lubricious sleeves are typically polymeric tubes,particularly thin-walled polymeric tubes made from a lubricious polymeror a polymer which may be lubricated on at least one side. The polymerictube typically has a length in the range from 5 cm to 90 cm, preferablyfrom 10 cm to 35 cm, an inner diameter (for a single lumen) in the rangefrom 2 mm to 12 mm, preferably in the range from 2 mm to 6 mm, and awall thickness in the range from 0.01 mm to 0.05 mm, preferably from0.02 mm to 0.04 mm. Exemplary polymers for the polymeric tube includepolytetrafluoroethylene (PTFE), polyethylene (PE), perfluoroalkoxy(PFA), polyurethane (PU), perfluoromethylvinylether (MFA),perfluoropropylvinylether (PPVE), and copolymers thereof. Preferredpolymers include tensilized PTFE/PPVE copolymers.

In a second embodiment of the present invention, the evertable,lubricious sleeve may be attached to or formed as part of an outersheath structure typically comprising a relatively stiff andnon-evertable tube. The tube will be disposed coaxially over the pushertube and have a distal end extending from “an outside” end of theevertable, lubricious sleeve, i.e., the end which is positioned to moveover the outside of the pusher tube. Prior to deployment, the “outsideend” of the lubricious sleeve will be positioned at or near the distalend of the pusher tube. During deployment, the outside end will remaingenerally stationary relative to the body lumen as the distal end of thepusher tube is advanced distally relative to the body lumen to evert andadvance a leading fold of the sleeve over the distal end of the pushertube.

The non-evertable sheath, prior to deployment of the sleeve, willtypically cover most of the pusher tube and allow the user to position,hold, or otherwise manipulate the system prior to advancement of thepusher tube. The non-evertable sheath is advantageous since, forexample, it can be used to advance the luminal access system of thepresent invention through an endoscope. Once the system is in place, thesheath can be held relative to the endoscope to immobilize the proximalend of the lubricious sleeve as the pusher tube is advanced relative tothe body lumen. Thus, in at least one aspect, the non-evertable portionof the sheath serves to replace the anchor ring 20 of the prior artMemcath™ catheter illustrated in FIG. 1. Alternatively, the user couldselectively reposition the proximal end of the lubricious sleeve usingthe non-everting sheath should it be desirable for any reason to do so.

Typically, the non-evertable sheath will comprise a flexible polymerictube. The flexible tube usually has a length in the range from 5 cm to50 cm, an inner diameter in the range from 1 mm to 12 mm, and a wallthickness in the range from 0.01 mm to 0.1 mm. Suitable polymers includepolyimide, Pebax, polyethylene, fluoropolymers, and the like.

In a third embodiment of the luminal access system of the presentinvention, the system further comprises a lumen tube having a distalend, a proximal end, and a central passage between the distal end andthe proximal end. The lumen tube will be positionable within the axialpassage of the pusher tube and will be attached at its distal end to the“inner end” of the lubricious sleeve, i.e., the end positioned withinthe central passage of the pusher tube. Thus, the lumen tube will beattached at the end of the lubricious sleeve which is generally locatedor stowed within the axial passage of the pusher tube. The other or“outer end” of the lubricious sleeve will typically be attached to thenon-evertable sheath as discussed above. The lumen tube will extendgenerally in a proximal direction from the sleeve, that is in adirection toward the proximal end of the pusher tube. The lumen tubewill be able to slide freely within the axial passage of the pusher tubeand will typically be advanced distally relative to the pusher tube asthe pusher tube is advanced distally within the body lumen. That is, thelumen tube will move in unison and synchrony with the inner end of thelubricious sleeve to which it is attached. Conversely, pullingproximally on the lumen tube can pull back or reverse deployment of thesleeve in the body lumen. Thus, the preferred embodiments of the presentinvention which comprise both the non-evertable sheath and the lumentube allow for bidirectional deployment and positioning of the accesssystem.

The lumen tube will typically be composed of a polymer, such aspolyethylene, Pebax, polyimide, fluoropolymers, and the like. The lumentube typically will have a length sufficient with the pusher tube fullyextended to provide luminal access for the insertion or manipulation ofvarious devices, such as guidewires, wire baskets, lithotripters, andthe like. The lumen tube may have a luer or other conventional medicalfitting on its proximal end to allow connection of the lumen tube to anaspiration source, infusion source, or other therapeutic or diagnosticsystem.

The lumen tube is beneficial since it improves access through the pushertube of the luminal access system. It will be appreciated that withoutthe lumen tube, access would have to be made directly through the axialpassage of the pusher tube. In many cases, such access may besufficient. In other instances, for example when a portion of thelubricious sleeve remains within the axial passage of the pusher tube,such access may be compromised. Use of the lumen tube which is directlyconnected to the inner end of the lubricious sleeve, however, assuresthat access through the pusher tube can be easily effected regardless ofthe position of the lubricious sleeve.

It will be appreciated that each of the embodiments of the presentinvention just described may be employed individually or in combinationwith each other. In the exemplary embodiments, the luminal access systemwhich is illustrated will combine each of the bendable distal end of thepusher tube, non-evertable proximal sheath portion, and lumen tube. Eachof these aspects of the present invention, however, are considered todefine separate inventions.

In a second aspect of the present invention, methods for accessing abody lumen comprise disposing an everted edge of a lubricious sleeveadjacent to an access point on a body lumen, typically a natural bodyorifice, an incision to access a body lumen, or a tissue tract formedthrough tissue to the body lumen. A pusher tube, optionally having abendable distal end, is distally advanced against a proximal side of theeverted edge to distally advance the everted edge into the body lumen.An outer end of the sleeve is immobilized relative to the pusher tube,and a lumen tube is drawn into the body lumen by an inner end of thesleeve.

In preferred aspects of the method, the outer end of the sleeve isimmobilized using a sheath tube secured to said outer end. As describedabove in connection with the systems of the present invention, thesheath may conveniently be a non-everting tube connected to or anextension of the lubricious sleeve. The pusher tube may be advancedthrough tortuous lumens, optionally being advanced over a guidewiredisposed in the body lumen. In such cases, the distal portion of thepusher tube is typically conformable to track through the lumen or overthe guidewire and the proximal portion of the pusher tube has sufficientcolumn strength to push the distal portion in the distal direction. Oncein place, a material or instrument may be introduced through the passageof the lumen tube and out of the distal end of the pusher tube.Optionally, the lubricious sleeve may be positioned in advance throughan endoscope or other access cannula prior to advancing the pusher tubeinto the body lumen. The body lumen is typically a natural body lumen,such as a urethra, a ureter, a blood vessel, a hepatic duct, a cysticduct, a cervical canal, a fallopian tube, or the like.

A particular advantage of the present invention is the ability toreverse deployment of the lubricious sleeve at any time during aprocedure by pulling proximally the inner end of the sleeve, typicallyvia the attached lumen tube. Pulling on the lumen tube will cause thepreviously deployed sleeve to be pulled from the adjacent tissue backinto the axial passage of the pusher tube. In this way, trauma to theluminal wall resulting from withdrawal of the system is reduced and therisk of transport of pathogens, tumor cells, cellular debris, and otherpotential contaminants along the lumen is lessened.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a Memcath™ luminal access catheter of the prior art.

FIG. 2 is a perspective view of a luminal access system constructed inaccordance with the principles of the present invention shown withportions broken away.

FIG. 3 is a detailed view of the distal end of the luminal access systemof FIG. 2, shown in partial section.

FIG. 3A is a detailed view of the distal end shown with a pull wireuseful for steering.

FIG. 3B is a detailed view of the distal end of the pusher tube.

FIGS. 4-6 illustrate use of the luminal access system of FIGS. 2 and 3for accessing a kidney using endoscopic deployment through the bladder.

DETAILED DESCRIPTION OF THE INVENTION

The systems and methods of the present invention are useful forproviding access through any natural or created body lumen of a patientwhere it is desired to temporarily or permanently place an access tubeor a structure. Most commonly, the systems and methods will be used toplace a drainage, infusion, or other interventional tube or instrumentthrough a natural body lumen to a target site within the body lumen or ahollow body organ connected to the natural body lumen. The methodsdescribed in the following description are directed specifically ataccessing a kidney through a ureter where the access system of thepresent invention has been deployed through an endoscope passed throughthe urethra. It will be appreciated, however, that the principles of thepresent invention will apply more broadly as discussed above.

Referring now to FIGS. 2 and 3, an exemplary luminal access system 20constructed in accordance with the principles of the present inventioncomprises a pusher tube 22 having a distal end 24, a proximal end 26,and an axial passage 28 extending from the proximal end to the distalend. An evertable, lubricious sleeve 30 everts or folds back over thedistal end 24 of the pusher tube 22 so that an inner end 32 of thesleeve is located within the lumen or axial passage 28 of the pushertube 22 and an outer end 34 is located over the exterior of the pushertube.

The outer end 34 of the sleeve 30 is attached to a sheath 36 which istypically non-evertable (i.e., having sufficient stiffness to allow theuser to manipulate the sleeve from the proximal end and is coaxiallyreceived over the exterior of the pusher tube 22. As described above,both the evertable, lubricious sleeve 30 and the sheath 36 will usuallybe composed of polymers, and the attachment at outer end 34 can be madein any manner suitable for attaching the polymers, e.g., by heatwelding, the use of adhesives, sonic welding, the use of staples orother fasteners, or the like. A hub 37 may be at the proximal end of thesheath 36 to provide a sliding seal against the pusher tube 22.

A lumen tube 40 is coaxially received within the axial passage 28 of thepusher tube 22. The distal end 32 of lubricious sleeve 30 is attached tothe distal end of the lumen tube 40, as best seen in FIG. 3. A luer orother attachment fitting 46 may be provided on a proximal end 44 of thelumen tube 40, and a proximal portion of the lumen tube will typicallypass out of the pusher tube 22 as shown in FIG. 2.

In a preferred aspect of the present invention, the pusher tube 22 willbe reinforced, at least over a distal portion thereof. As shown in FIG.3, the distal portion is reinforced by a flat ribbon wire coil 50comprising adjacent turns which are spaced apart by a distance which isgreater than the width of the wire. In this way, the distal portion ofthe pusher tube is radially reinforced to provide hoop strength whileremaining sufficiently bendable to pass through relatively tortuous bodylumens and bypass obstructions within the body lumens. To achieve such aflexibility, at least the distal portion of the pusher tube willtypically be composed of a relatively soft polymer, such as low densitypolyethylene (LDPE). Optionally, a pull wire 52 or other steeringmechanism may be provided to deflect the tip 24, as shown in brokenline, to facilitate advancement.

The proximal portion of the pusher tube will generally be less bendableand therefore more pushable than the distal section just described. Theproximal portion will typically be composed of a stiffer polymer, suchas high density polyethylene (HDPE) and may optionally be reinforcedusing a flat or circular coil, braiding, hoop structures, or the like.As illustrated in FIG. 3, reinforcement of the proximal end comprisesthe same wired coil used to reinforce the distal end, where the adjacentturns of the wire coil 50′ are spaced together much more closely than inthe distal portion. Such close spacing enhances not only the hoopstrength but also the column strength of the distal portion of thepusher tube. The relative lengths of the distal portion and the proximalportion may vary greatly. Typically, the relatively bendable distalportion of the pusher tube will have a length in the range from 0.5 cmto 4 cm while the relatively more pushable proximal section of thepusher tube will have a length in the range from 4 cm to 90 cm.

As a further optional feature, the distal end 24 of the pusher tube maybe configured to enhance lubricity and/or hoop strength. As thelubricious sleeve 30 will be everted over the distal end 24, it isdesirable that the friction between the sleeve and the distal end beminimized. The preferred materials of the lubricious sleeve, asdescribed above, are inherently lubricious. Optionally, friction may befurther reduced by enhancing the lubricity of the distal end 24. Thismay be done by selecting the proper materials, and/or lubricants, and/ortip profile for the distal-most end.

A specific distal tip configuration 24′ is illustrated in FIG. 3B. Thepusher tube 24 terminates in a short section (d=1.5 mm) of highlubricity LDPE with the distal end folded back and heat set as shown onFIG. 3. The remaining length of the tube 24 may be composed of LDPE witha higher coefficient of friction. A ring 70 of radiopaque material, suchas gold or platinum, is positioned between the tip 24′ and the beginningof the wire coil 50′. The ring serves both as a radiopaque marker and asa termination point for the coil. A reinforcement sleeve 72 is providedover the transition point between the high pitch and low pitch sectionsof the reinforcing coil.

Referring now to FIGS. 4-6, use of the luminal access system 20 foraccessing a kidney K will be described. As illustrated in FIG. 4, thekidney K is located at the end of the patient's ureter U which extendsbetween the kidney and the patient's bladder B. The luminal accesssystem may be deployed through an access cannula, typically within anendoscope E, passed through the patient's urethra UA. The distal end ofthe pusher tube is then used to advance the everting fold EF of theaccess system through the ureter optionally under imaging if anendoscope is being used to provide an access cannula.

As shown in FIG. 5, the everting fold EF of the lubricious sleeve 30 isadvanced by pushing the proximal portion of the pusher tube 22 forwardlyin the direction of arrow 60 into sheath 36. The proximal portion of thepusher tube 22 will remain outside the patient and available for manualadvancement by the physician. Typically, the physician will hold aproximal portion of the sheath 36 which will in turn immobilize thealready deployed portion of the lubricious sleeve 30 within the ureterU. As the pusher tube 22 is manually advanced, the sleeve 30 is pulledfrom the passage of the pusher tube 22. Lumen tube 40 will be carrieddistally in the direction of arrow 62 as its distal end is dragged bythe distal end 32 of the sleeve 30. Because the distal end 24 of thepusher tube acts like a pulley, sleeve material is pulled from thecentral passage of the pusher tube 22 at a rate which is twice as fastas the rate at which the pusher tube 22 is being manually advanced.Thus, the lumen tube 40 will advance at a rate twice as fast as thepusher tube 20 is being advanced.

As shown in FIG. 5, the everting fold EF of the sleeve 30 has justreached an occluding structure within the ureter, typically a kidneystone KS. The bendable proximal portion of the pusher tube isadvantageous in that it facilitates bypass of the kidney stone by theluminal access system as it is advanced.

As shown in FIG. 6, the pusher tube 22 can continue to be advanced untilthe everting fold EF has reached the interior of the kidney. The luerfitting 46 of the lumen tube 40 is then available for connection to adrainage source, infusion source, or other therapeutic or diagnosticapparatus, where it is desired to be connected to the interior of thekidney K.

1. A luminal access system comprising: an evertable, lubricious sleeve;and a pusher tube having a distal end, a proximal end, and an axialpassage between the distal and proximal ends, wherein the sleeve ispositionable over the exterior of the tube to evert over the distal endinto the axial passage, and wherein a distal portion of the pusher tubeis circumferentially reinforced and relatively more bendable than aproximal portion of the tube.
 2. A luminal access system as in claim 1,wherein the sleeve comprises a polymeric tube.
 3. A luminal accesssystem as in claim 2, wherein the polymeric tube has a length in therange from 5 cm to 90 cm, an inner diameter in the range from 2 mm to 12mm, and a wall thickness in the range from 0.01 mm to 0.05 mm.
 4. Aluminal access system as in claim 2, wherein the polymer is a lubriciouspolymer.
 5. A luminal access system as in claim 2, wherein the polymeris lubricated.
 6. A luminal access system as in claim 2, wherein thepolymer is selected from the group consisting of polytetrafluoroethylene(PTFE), polyethylene (PE), perfluoroalkoxy (PFA), polyurethane (PU),perfluoromethylvinylether (MFA), perfluoropropylvinylether (PPVE).
 7. Aluminal access system as in claim 6, wherein the polymer comprisestensilized PTFE/PPVE copolymer.
 8. A system as in claim 1, wherein thepusher tube comprises a polymeric tube.
 9. A system as in claim 8,wherein the polymer is selected from the group consisting of PE,fluoropolymers, and Pebax, and polyimide (PI).
 10. A system as in claim9, wherein the distal portion of the pusher tube comprises a low densitypolyethylene and the proximal portion of the pusher tube comprises ahigh density polyethylene.
 11. A system as in claim 10, wherein thedistal portion of the pusher tube is reinforced with a wire coil.
 12. Asystem as in claim 11, wherein the wire coil comprises a ribbon wirewith adjacent turns spaced apart by a distance greater than the width ofthe ribbon.
 13. A system as in claim 8, wherein the pusher tube furthercomprises a radiopaque ring near its distal end.
 14. A system as inclaim 1, wherein the sleeve comprises a sheath structure having anon-evertable portion attached proximal to the evertable, lubricioussleeve.
 15. A system as in claim 14, wherein the non-evertable portionof the sheath comprises a flexible but non-everting tube.
 16. A systemas in claim 15, wherein the non-everting tube has a length in the rangefrom 5 cm to 50 cm, an inner diameter in the range from 1 mm to 12 mm,and a wall thickness from 0.01 mm to 0.1 mm.
 17. A system as in claim16, wherein the tube comprises a polymer.
 18. A system as in claim 17,wherein the polymer is selected from the group consisting of PE,flouropolymers, Pebax, and PI.
 19. A system as in claim 1, furthercomprising a lumen tube having a distal end, a proximal end, and acentral passage therebetween, wherein the lumen tube is positionablewithin the axial passage of the pusher tube and is attached at itsdistal end to the distal end of the sleeve.
 20. A system as in claim 19,wherein the lumen tube comprises a polymer.
 21. A system as in claim 20,wherein the polymer is selected from the group consisting of PE,fluoropolymers, Pebax, and PI.
 22. A system as in claim 18, furthercomprising a luer fitting on the proximal end of the lumen tube.
 23. Aluminal access system comprising: a sheath structure having anon-evertable proximal portion and an evertable, lubricious distalsleeve portion; and a pusher tube having a distal end, a proximal end,and an axial passage between the distal and proximal ends, wherein thedistal sleeve portion of the sheath is positionable over the exterior ofthe tube to evert over the distal end into the axial passage.
 24. Asystem as in claim 23, wherein the non-evertable portion of the sheathcomprises a flexible tube.
 25. A system as in claim 24, wherein the tubehas a length in the range from 5 cm to 50 cm, an inner diameter in therange from 2 mm to 12 mm, and a wall thickness from 0.01 mm to 0.1 mm.26. A system as in claim 25, wherein the tube comprises a polymer.
 27. Asystem as in claim 26, wherein the polymer is selected from the groupconsisting of PE, fluoropolymers, Pebax, and PI.
 28. A luminal accesssystem as in claim 23, wherein the lubricious, distal sleeve comprises apolymeric tube.
 29. A luminal access system as in claim 28, wherein thepolymeric tube has a length in the range from 5 cm to 50 cm, an innerdiameter in the range from 2 mm to 12 mm, and a wall thickness in therange from 0.01 mm to 0.05 mm.
 30. A luminal access system as in claim28, wherein the polymer is a lubricious polymer.
 31. A luminal accesssystem as in claim 28, wherein the polymer is lubricated.
 32. A luminalaccess system as in claim 28, wherein the polymer is selected from thegroup consisting of polytetrafluoroethylene (PTFE), polyethylene (PE),perfluoroalkoxy (PFA), polyurethane (PU), perfluoromethylvinylether(MFA), and perfluoropropylvinylether (PPVE).
 33. A luminal access systemas in claim 32, wherein the polymer comprises tensilized PTFE/PPVEcopolymer.
 34. A system as in claim 23, wherein a distal portion of thepusher tube is circumferentially reinforced and relatively more bendablethan a proximal portion of the tube.
 35. A system as in claim 34,wherein the pusher tube comprises a polymeric tube.
 36. A system as inclaim 35, wherein the polymer is selected from the group consisting ofPE, fluoropolymers, Pebax, and PI.
 37. A system as in claim 36, whereinthe distal portion of the pusher tube comprises a low densitypolyethylene and the proximal portion of the pusher tube comprises ahigh density polyethylene.
 38. A system as in claim 37, wherein thedistal portion of the pusher tube is reinforced with a wire coil.
 39. Asystem as in claim 38, wherein the wire coil comprises a ribbon wirewith adjacent turns spaced apart by a distance greater than the width ofthe ribbon.
 40. A system as in claim 35, wherein the pusher tube furthercomprises a radiopaque ring near its distal end.
 41. A system as inclaim 23, further comprising a lumen tube having a distal end, aproximal end, and a central passage therebetween, wherein the lumen tubeis positionable within the axial passage of the pusher tube and isattached at its distal end to the inner end of the sleeve.
 42. A systemas in claim 41, wherein the lumen tube comprises a polymer.
 43. A systemas in claim 42, wherein the polymer is selected from the groupconsisting of PE, fluoropolymers, Pebax, and PI.
 44. A system as inclaim 41, further comprising a luer fitting on the proximal end of thelumen tube.
 45. A luminal access system comprising: an evertable,lubricious sleeve having a distal end and a proximal end; a pusher tubehaving a distal end, a proximal end, and an axial passage between thedistal and proximal ends, wherein the sleeve is positionable over theexterior of the tube to evert the distal end of the sleeve over thedistal end of the tube into the axial passage; and a lumen tube having adistal end, a proximal end, and a central passage between the distal endand the proximal end, wherein the lumen tube is positionable within theaxial passage of the pusher tube and attached at its distal end to thedistal end of the sleeve.
 46. A system as in claim 45, wherein the lumentube comprises a polymer.
 47. A system as in claim 46, wherein thepolymer is selected from the group consisting of PE, fluoropolymers,Pebax, and PI.
 48. A system as in claim 45, further comprising a luerfitting on the proximal end of the lumen tube.
 49. A system as in claim45, wherein a distal portion of the pusher tube is circumferentiallyreinforced and relatively more bendable than a proximal portion of thetube.
 50. A system as in claim 49, wherein the pusher tube comprises apolymeric tube.
 51. A system as in claim 50, wherein the polymer isselected from the group consisting of PE, fluoropolymers, Pebax, and PI.52. A system as in claim 51, wherein the distal potion of the pushertube comprises a low density polyethylene and the proximal portion ofthe pusher tube comprises a high density polyethylene.
 53. A system asin claim 52, wherein the distal portion of the pusher tube is reinforcedwith a wire coil.
 54. A system as in claim 50, wherein the pusher tubefurther comprises a radiopaque ring near its distal end.
 55. A system asin claim 53, wherein the wire coil comprises a ribbon wire with adjacentturns spaced apart by a distance in the range from 0.2 mm to 2 mm.
 56. Aluminal access system as in claim 45, wherein the sleeve comprises apolymeric tube.
 57. A luminal access system as in claim 56, wherein thepolymeric tube has a length in the range from 5 cm to 50 cm, an innerdiameter in the range from 2 mm to 12 mm, and a wall thickness in therange from 0.01 mm to 0.05 mm.
 58. A luminal access system as in claim56, wherein the polymer is a lubricious polymer.
 59. A luminal accesssystem as in claim 56, wherein the polymer is lubricated.
 60. A luminalaccess system as in claim 56, wherein the polymer is selected from thegroup consisting of polytetrafluoroethylene (PTFE), polyethylene (PE),perfluoroalkoxy (PFA), polyurethane (PU), perfluoromethylvinylether(MFA), and perfluoropropylvinylether (PPVE).
 61. A luminal access systemas in claim 60, wherein the polymer comprises tensilized PTFE/PPVEcopolymer.
 62. A system as in claim 45, wherein the sleeve comprises asheath structure having a non-evertable portion attached proximal to theevertable, lubricious sleeve.
 63. A system as in claim 62, wherein thenon-evertable portion of the sheath comprises a flexible tube.
 64. Asystem as in claim 63, wherein the tube has a length in the range from 5cm to 50 cm, an inner diameter in the range from 1 mm to 12 mm, and awall thickness from 0.01 mm to 0.1 mm.
 65. A system as in claim 63,wherein the tube comprises a polymer.
 66. A system as in claim 65,wherein the polymer is selected from the group consisting of PE,fluoropolymers, Pebax, and PI.
 67. A method for accessing a body lumen,said method comprising: disposing an everted edge of a lubricious sleeveadjacent to an access point on the body lumen; and distally advancing apusher tube against a proximal side of the everted edge to distallyadvance the everted edge into the body lumen, wherein an outer proximalend of the sleeve is immobilized relative to the pusher tube, andwherein a lumen tube is drawn into the body lumen by an inner distal endof the sleeve.
 68. A method as in claim 67, further comprisingimmobilizing the outer proximal end of the sleeve using a sheath tubesecured to said outer proximal end.
 69. A method as in claim 67, whereinthe pusher tube is advanced over a guidewire disposed in the body lumen.70. A method as in claim 69, wherein a distal portion of the pusher tubeis conformable to track the guidewire and a proximal portion of thepusher tube has sufficient column strength to push the distal portionover the guidewire.
 71. A method as in claim 67, further comprisingintroducing or removing a material or instrument through a lumen of thelumen tube.
 72. A method as in claim 67, wherein the lubricious sleeveis positioned through an endoscope prior to advancing the pusher tube.73. A method as in claim 67, wherein the lubricious sleeve is initiallydisposed in an axial passage of the pusher tube and the pusher tube. 74.A method as in claim 73, wherein the lubricious sleeve is withdrawn fromthe axial passage as the pusher tube is advanced through the naturalbody lumen.
 75. A method as in claim 67, wherein the natural body lumenis selected from the group consisting of a urethra, a ureter, a bloodvessel, a hepatic duct, a cystic duct, a cervical canal, and a fallopiantube.